As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE OXYGEN SYSTEM WAS BEING SERVICED, AT 3/4 PRESSURE THE AIRCRAFT’S PRESSURE GAUGE BECAME UNREADABLE AND A LEAKING SOUND DISCOVERED. OXYGEN CART WAS TURNED OFF AND LEAK INVESTIGATED. LEAKAGE COULD BE FELT ON THE BOTTOM OF THE GAUGE WHEN TECHNICIAN RAN FINGERS AROUND IT AT WHICH POINT THE GAUGE BLEW APART. REPLACED THE GAUGE.